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Balloon Helicopter
A balloon helicopter is a flying toy consisting of a latex toy balloon and a plastic propeller, derived from the simple balloon rocket. The most important feature is the hollow propeller hub which directs air into a passage in each propeller blade. The air passages channel air to the blade tips such that air escapes in a fine jet tangentially. The air jets on the blade tips causes the entire toy to spin, the blades have a positive angle of attack so the blades experience a lifting force as they push air downwards. It can attain a height of approximately 12 meters (40 feet). Full-scale helicopters have been built around this tip jet A tip jet is a jet nozzle at the tip of some helicopter rotor blades, used to spin the rotor, much like a Catherine wheel firework. Tip jets replace the normal shaft drive and have the advantage of placing no torque on the airframe, thus not re ... configuration. See also * Balloon rocket External links Physics teacher Robert Douglas discus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toy Balloon
A toy balloon or party balloon, is a small balloon mostly used for decoration, advertising and children's toys. Toy balloons are usually made of rubber or aluminized plastic, and inflated with air or helium. They come in a great variety of sizes and shapes, but are most commonly 10 to 30 centimetres in diameter. Toy balloons are not considered to include "sky lanterns" (hot-air paper balloons), although these too are or were used as child toys in some parts of the world. According to The Journal of the American Medical Association, out of 373 children who died in the US between 1972 and 1992 after choking on children's products, nearly a third choked on latex balloons. The Consumer Products Safety Commission found that children had inhaled latex balloons whole (often while trying to inflate them) or choked on fragments of broken balloons. ''Parents'', a monthly magazine about raising children, advised parents to buy Mylar balloons instead of latex balloons. History Early b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller (aircraft)
An aircraft propeller, also called an airscrew,Beaumont, R.A.; ''Aeronautical Engineering'', Odhams, 1942, Chapter 13, "Airscrews". converts rotary motion from an engine or other power source into a swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached several radial airfoil-section blades such that the whole assembly rotates about a longitudinal axis. The blade pitch may be fixed, manually variable to a few set positions, or of the automatically variable "constant-speed" type. The propeller attaches to the power source's driveshaft either directly or through reduction gearing. Propellers can be made from wood, metal or composite materials. Propellers are most suitable for use at subsonic airspeeds generally below about , although supersonic speeds were achieved in the McDonnell XF-88B experimental propeller-equipped aircraft. Supersonic tip-speeds are used in some aircraft like the Tupolev Tu-95, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balloon Rocket
A balloon rocket is a rubber balloon filled with air or other gases. Besides being simple toys, balloon rockets are a widely used as a teaching device to demonstrate basic physics. How it works To launch a simple rocket, the untied opening of an inflated balloon is released. The elasticity of the balloon contracts the air out through the opening with sufficient force and the resulting pressure creates a thrust which propels the balloon forward as it deflates. It is usual for the balloon to be propelled somewhat uncontrollably (or fly in and unstable centre of mass), as well as turbulence that occur in the opening as the air escapes, causing it to flap rapidly and disperses air outwards in random direction. Near the end of its deflation, the balloon may suddenly shoot quickly in the air shortly before it drops down, due to the rubber rapidly squeezes out the remaining air inside as it reaches the inclination to return to its uninflated size. The flight altitude only amounts to som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tip Jet
A tip jet is a jet nozzle at the tip of some helicopter rotor blades, used to spin the rotor, much like a Catherine wheel firework. Tip jets replace the normal shaft drive and have the advantage of placing no torque on the airframe, thus not requiring the presence of a tail rotor. Some simple monocopters are composed of nothing but a single blade with a tip rocket. Tip jets can use compressed air, provided by a separate engine, to create jet thrust. Other types use a system that functions similarly to the afterburner (reheat) on a conventional jet engine, except that instead of reheating a gas jet, they serve as the primary heater, creating greater thrust than the flow of pre-compressed air alone; the best description of this is ''thrust augmentation''. Other designs includes ramjets or even a complete turbojet engine. Some, known as Rocket On Rotor systems, involve placing rockets on the tips of the rotor blades that are fueled from an onboard fuel tank. If the helicopter's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balloon Rocket
A balloon rocket is a rubber balloon filled with air or other gases. Besides being simple toys, balloon rockets are a widely used as a teaching device to demonstrate basic physics. How it works To launch a simple rocket, the untied opening of an inflated balloon is released. The elasticity of the balloon contracts the air out through the opening with sufficient force and the resulting pressure creates a thrust which propels the balloon forward as it deflates. It is usual for the balloon to be propelled somewhat uncontrollably (or fly in and unstable centre of mass), as well as turbulence that occur in the opening as the air escapes, causing it to flap rapidly and disperses air outwards in random direction. Near the end of its deflation, the balloon may suddenly shoot quickly in the air shortly before it drops down, due to the rubber rapidly squeezes out the remaining air inside as it reaches the inclination to return to its uninflated size. The flight altitude only amounts to som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Educational Toys
Educational toys (sometimes also called "instructive toys") are objects of play, generally designed for children, which are expected to stimulate learning. They are often intended to meet an educational purpose such as helping a child develop a particular skill or teaching a child about a particular subject. They often simplify, miniaturize, or even model activities and objects used by adults. Although children are constantly interacting with and learning about the world, many of the objects they interact with and learn from are not toys. Toys are generally considered to be specifically built for children's use. A child might play with and learn from a rock or a stick, but it would not be considered an educational toy because 1) it is a natural object, not a designed one, and 2) it has no expected educational purpose. The difference lies in perception or reality of the toy's intention and value. An educational toy is expected to educate. It is expected to instruct, promot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
